A former WorkSafe inspector says procedures at airports, ports and MIQ facilities are far too relaxed to prevent one of the new strains of Covid-19 getting into the community.
Opposition parties are also accusing the government of drifting into a summer slumber.
But officials say they are still at the wheel and will not hesitate to introduce more protections, if required.
It comes as the UK and South African Covid-19 variants, now running rampant around the globe, are confirmed in New Zealand's managed isolation facilities.
From Friday, travellers from the US and UK will need to provide a negative test before departing for New Zealand, and the government is investigating whether this should be extended to other Covid-19 hotspots.
But with the new strains now inside New Zealand's isolation facilities, there are calls for more to be done.
Allister Rose, a former police officer and WorkSafe inspector who now runs a health and safety consultancy, said his contacts working at airports, ports and MIQ hotels fear another outbreak.
"The sort of thing that I'm hearing is that everyone's on holiday at the moment - everyone's at the beach," he said.
"They see their colleagues going off to the beach and they're waiting for their turn to head off to the beach as well. So people are feeling a little bit too relaxed and they're not being checked by WorkSafe so we don't actually know how efficient our workers are at MIQ or any of the ports."
Rose said WorkSafe needs to conduct an urgent audit of border procedures and protocols to make sure things are up to scratch.
"A number of my former colleagues who are working in these types of facilities are concerned because they aren't being checked - they don't have any interaction whatsoever with WorkSafe.
"There isn't anything coming down from the prime minister about how we should be dealing with this. The prime minister's absolutely okay to be commenting on what's happening in America, but she's absolutely absent about a potential catastrophe that's just about to happen.
"In my view, Parliament should be recalled... It's time to step up and start to manage before our economy is absolutely wrecked."
In a statement provided after this story was initially published, head of Managed Isolation and Quarantine, Brigadier Jim Bliss strongly refuted claims of staff and border complacency over summer and said he was confident in the staff and systems in place.
"Our priority is the safety of returnees, staff, families and communities," he said.
"One of the key reasons New Zealanders could go to the beach this year and enjoy summer was because of the ongoing work of our dedicated frontline staff who keep New Zealand safe."
Facilities were at 96 percent capacity during this period and staff were extra vigilant given the situation unfolding overseas, he said.
"WorkSafe is an independent regulator. MIQ takes its obligation to our workforces safety extremely seriously and is fully committed to ensuring WorkSafe is notified as soon as possible after becoming aware of any notifiable event having occurred."
WorkSafe undertook inspections of a number of MIQ facilities during August and September, and found these facilities were "clearly striving to meet their health and safety obligations to staff", he said.
Bliss said the government would continue to work proactively to make the system as strong and safe as possible.
"An example of this, is the Infection Prevention Control audit tool, which was developed and used by the Ministry of Health in conjunction with District Health Boards to carry out two audits of the 32 MIQ facilities - one in late July/August 2020, and the second in late September/early October 2020. The audits will serve as a baseline for future audits, which will continue to be carried out regularly. A third round of audits got underway on 9 December.
"There were a total of 155 findings in the first audit and 132 in the second. All findings from both audits have been addressed. "
The National Party, meanwhile, is accusing the government of sitting on its hands.
Leader Judith Collins said with the highly infectious variants already here, it is critical the vaccine rollout is fast-tracked.
"It is ridiculous not to have a plan to roll out the vaccines when they're available and let New Zealanders know when they're going to be available," she said.
"I've heard this morning reports from Canada, where they've got five times the amount of vaccine that they need to vaccinate their whole country, and we seem to have none."
Collins said people were worried about another border failure and lockdown.
"It's very important that the New Zealand government doesn't go asleep on this issue and declare victory well before it's time to declare any victory at all."
ACT leader David Seymour said circumstances were changing quickly yet the government is silent.
"The calculus of Covid is changing around the world so rapidly and New Zealand appears to still be on holiday. We've got to do better than that because the stakes are a rapid outbreak and a five-week, tough lockdown to bring it under control."
Duty minister Peeni Henare said in a statement that further action has been taken over summer to strengthen NZ's borders, and the government will not hesitate to introduce more protections.
"These are on top of the ongoing strengthening of our MIQs, which represent the most robust border protections anywhere in the world," he said.
The latest actions include introducing day zero testing for returnees from higher risk countries and requiring these people to stay in their rooms in managed isolation until they return a negative test.
"We will also be requiring pre-departure testing before returnees from the UK and the US can enter New Zealand starting from this Friday, and are looking closely at other long-haul routes.
"We are constantly reviewing and strengthening our settings based on the most up to date information and advice. Ministers and officials have been in near daily contact during the summer break to ensure New Zealanders continue to be kept safe from the virus."
Henare said work was continuing at pace to get New Zealanders vaccinated, with the first frontline workers expected to get the jab in April.
"New Zealand's Medsafe is working closely with its Australian counterpart, the Therapeutic Goods Administration, regarding the data both agencies are receiving from pharmaceutical companies about Covid-19 vaccines and any approval decisions made by Australia.
"Medsafe has streamlined its approval processes to move swiftly, but without rushing or compromising safety in any way. It is critical the public has confidence in the safety of vaccines."
WorkSafe was not immediately available for comment.
- If you have symptoms of the coronavirus, call the NZ Covid-19 Healthline on 0800 358 5453 (+64 9 358 5453 for international SIMs) or call your GP - don't show up at a medical centre